I thought that may be it, but was thinking that was for single missions but not within a campaign? I'll try it out.
Well, I don't want calm seas all the time, but the way it changes currently such as on my last patrol(3 june 1944- 29 July 1944) is a bit much. Weather was Atlantic like, bit of an immersion killer for a pacific sim. Sure, heavy seas are nice for masking attacks, especially in shallow waters but if like that all the time, means player rarely gets depth charged, which is anti climatic. Heavy seas makes night surface attacks difficult, the bow and stern wakes makes it easier for enemy to spot, slows speed and maneuverability on surface, makes some ships impossible to torpedo as their draft is shallow and waves cause them to ride higher. Again, don't mind the variety as attacks were made under different conditions but the current interval in that campaign file is 5 hours, so if that is the setting need to change, no wonder weather was so erratic. It's about balance.